The invention relates to the field of heating devices, and in particular relates to a gas heater. The gas heater comprises a base, and a housing which is erected on the base, wherein a net mask is arranged at the left end of the housing, and a heat insulation barrel is arranged in the housing; an air inlet tube, which is connected to a pressure regulating valve assembly through a solenoid valve, is mounted on the base; the pressure regulating valve assembly comprises a pressure regulating valve body, a knob rod assembly, a microswitch and a thermocouple solenoid valve; one end of the knob rod assembly extends out of the base; a knob is mounted on the knob rod assembly; an air outlet of the pressure regulating valve body is connected to a nozzle which is mounted at the bottom part of an ejection tube; a combustion head is mounted on the top part of the ejection tube; one end of an ignition needle is mounted to the combustion head while the other end of the ignition needle is connected to a pulse igniter; the pulse igniter is connected in series with the microswitch; one end of a thermocouple is mounted at the combustion head. The gas heater has the benefits that the gas heater can be continuously ignited or released and stopped at any time, so that the ignition efficiency can be improved, detonation can be avoided, and the stepless adjustment can be performed for the gas volume.